4 VETERINARY PARASITOLOGY 
to the walls and uprights being used for rubbing 
against, and so the disease is propagated from year 
to year. Among horses, grooming utensils, more 
particularly curry-combs, act as sources of mediate 
contagion. 
. Rats and mice suffer from a variety of favus, which 
is very contagious to cats and dogs, in which the lesions 
develop on those portions of the body which come in 
contact with the rodents. Hence it is common to find 
crusts on the paws and around the head, particularly 
on the ears. 
Ringworm in the Horse. 
The commonest varieties met with are Trichophyton 
and Microsporon. Favus in horses is rare. 
The disease is seen chiefly in foals and young horses, 
but older animals are not uncommonly affected. The 
eruption occurs in the form of small rounded patches 
on the trunk, particularly on the croup and shoulders, 
and also upon the head and neck. The hair on these 
first becomes erect, then matted. The parasites attack 
the hairs, which break off level with the skin, and fall 
out, cemented together by a scab. The bare patches 
left are of a slaty-grey colour, and covered with silvery 
scales. At first they are the size of a sixpence or a 
shilling, but spread from the periphery, and may attain 
the size of a two-shilling-piece, or become even larger 
still. After recovery, the hair covering the patches is 
at first darker in colour. 
Several varieties of trichophytosis are seen in horses. 
Trichophyton mentagrophytes affects the hair-follicles, and 
so, in addition to the bare patches described, one sees 
small pustules, which are quite visible after removal of 
the scab. The patches grow larger than in the variety just 
described, and may attain the size of a crown-piece. 
Prognosis.—Trichophytosis in the horse runs a benign 
